High temperature superconducting (HTS) generator was promising in the wind power applications for its advantages in the weight, size and thermal stability against load fluctuations, especially in the “direct-driven” design. A 100 kW generator was proposed for the demonstration of the feasibility of using HTS in 10 MW wind turbine generators. The electromagnetic design and optimization of the rotor were done using finite element method (FEM). The excitation coil of the rotor was designed considering variable working conditions. According to the numerical results, a number of suggestions in the design and winding techniques of the superconducting rotor were proposed.

High T _c superconducting (HTS) DC cable is a promising solution for large-scale power transmission over long distance. However, the refrigeration system for HTS cable is indispensable but undesirable. Considering that LNG (liquid natural gas) is now one kind of clean energy that is used more and more widely, it is possible to integrate HTS cable and LNG transportation into a single pipeline, resulting in a new energy transportation system- a HTS energy pipeline. In this paper, the principle and structure of the energy pipeline are first discussed and then the basic physical properties of the HTS tapes and liquid insulation medium in the LNG temperature range are analyzed. On this basis, a 10 kV/1 kA energy pipeline is designed, fabricated and tested.

With the increase of electricity demand and the rapid development of renewable energy generation, it is becoming more and more important to ensure the safety and stability of power grid, where a superconducting fault current limiter (SFCL) could play an important role. In recent years, a lot of research work has been done in China on the application of high temperature superconducting (HTS) power technology, especially in the aspects of superconducting fault current limiting technology, superconducting fault current limiting-breaking technology, superconducting fault current limiting- magnetic energy storage technology, and superconducting fault current limiting transformer technology. A number of demonstration projects on SFCL were also conducted. In this paper, the research progress of HTS fault current limiters (both AC and DC) in China in recent years is introduced, including the completed projects and the on-going work. The possible application direction of SFCL in the future is proposed.

In this paper, a general scheme of a 40 kV/2 kA resistive type DC superconducting fault current limiter (SFCL) is suggested, which could be utilized to suppress the surge current caused by short-circuit faults in voltage-source-converter HVDC (VSC-HVDC) power grids. This DC SFCL is designed and fabricated with 6 coil modules in parallel and 4 in series. In order to investigate the current-limiting performance of the DC SFCL under the rapidly rising fault current, the SFCL is tested on the platform with a pulsed DC impact generator. Besides the property of current limitation, the current capacity, insulation and quench recovery performance of such SFCL are also tested. Results indicate that the critical current of SFCL is larger than 2050 A at 69 K, and the DC withstand voltage is larger than 74 kV in 2 hours. During the 9kV DC impact test, the short-circuit current could be limited to 8842 A, and the quench recovery time is less than 200ms.

With the rapid development of the voltage source converter-based high voltage direct current (VSC-HVdc) power systems, as one of the methods for the suppression and interruption of short circuit current, resistive type dc superconducting fault current limiter (SFCL) is getting more and more attention. As SFCL will quench during the current limiting process, it is necessary to complete the quench and recovery process before the automatic reclosing of VSC-HVdc power systems. In this article, simulation and experimental analysis on SFCL are carried out. The superconducting tape used in the SFCL is the AMSC 8602 YBCO superconducting tape. It is concluded that the simulation results obtained by thermal conduction model using lumped parameter method are basically consistent with experimental results. With the increase of dc impact current and dc impact duration, recovery time of SFCL increases. Recovery time of the solenoid SFCL and the pancake SFCL under different placement modes differs, which is related to the heat dissipation space and the accumulation of bubbles.

The flux-coupling type superconducting fault current limiter (FC-SFCL) is suggested to suppress the surge current in voltage sourced converter based HVDC (VSC-HVDC) power systems. One 10 kV/400 A FC-SFCL module with two branches is designed and tested. For the FC-SFCL module, the two branches could use the same or different YBCO tapes. Furthermore the electromagnetic analysis and parameter calculation of the module are performed. In order to study the current-limiting performance of the FC-SFCL under the rapid change of fault current, a dynamic simulation model is established. Finally, the transient properties of FC-SFCL module are simulated and tested. According to the measurement results, the maximum impact current could be limited from 12kA to 6264A, and the largest resistance of SFCL module is about 1.5 Ω when the dc impact voltage is 10kV, which is close to the simulation results.